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A way forward for pointer equality in const eval #73398

Merged
merged 7 commits into from
Jun 23, 2020
Merged

A way forward for pointer equality in const eval #73398

merged 7 commits into from
Jun 23, 2020

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oli-obk
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@oli-obk oli-obk commented Jun 16, 2020

r? @varkor on the first commit and @RalfJung on the second commit

cc #53020

@rust-highfive rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jun 16, 2020
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oli-obk commented Jun 16, 2020 •
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r? @RalfJung for the miri changes and general scheme. I'll find someone to review everything else once we both can agree on a design

@rust-highfive rust-highfive assigned RalfJung and unassigned varkor Jun 16, 2020
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bors commented Jun 19, 2020

☔ The latest upstream changes (presumably #73504) made this pull request unmergeable. Please resolve the merge conflicts.

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oli-obk commented Jun 21, 2020

@bors r=varkor,RalfJung,nagisa

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bors commented Jun 21, 2020

📌 Commit e465b22 has been approved by varkor,RalfJung,nagisa

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 21, 2020
Manishearth added a commit to Manishearth/rust that referenced this pull request Jun 21, 2020
@Manishearth
Rollup merge of rust-lang#73398 - oli-obk:const_raw_ptr_cmp, r=varkor…
5d26903 
…,RalfJung,nagisa

A way forward for pointer equality in const eval

r? @varkor on the first commit and @RalfJung on the second commit

cc rust-lang#53020
@Manishearth Manishearth mentioned this pull request Jun 21, 2020
Closed
Manishearth added a commit to Manishearth/rust that referenced this pull request Jun 22, 2020
@Manishearth
Rollup merge of rust-lang#73398 - oli-obk:const_raw_ptr_cmp, r=varkor…
4958a5b 
…,RalfJung,nagisa

A way forward for pointer equality in const eval

r? @varkor on the first commit and @RalfJung on the second commit

cc rust-lang#53020
@Manishearth Manishearth mentioned this pull request Jun 22, 2020
Closed
Manishearth added a commit to Manishearth/rust that referenced this pull request Jun 22, 2020
@Manishearth
Rollup merge of rust-lang#73398 - oli-obk:const_raw_ptr_cmp, r=varkor…
5b219f2 
…,RalfJung,nagisa

A way forward for pointer equality in const eval

r? @varkor on the first commit and @RalfJung on the second commit

cc rust-lang#53020
This was referenced Jun 22, 2020
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bors added a commit to rust-lang-ci/rust that referenced this pull request Jun 23, 2020
@bors
Auto merge of rust-lang#73643 - Manishearth:rollup-68dr8fz, r=Manishe…
1557fb0 
…arth

Rollup of 9 pull requests

Successful merges:

 - rust-lang#72271 (Improve compiler error message for wrong generic parameter order)
 - rust-lang#72493 ( move leak-check to during coherence, candidate eval)
 - rust-lang#73398 (A way forward for pointer equality in const eval)
 - rust-lang#73472 (Clean up E0689 explanation)
 - rust-lang#73496 (Account for multiple impl/dyn Trait in return type when suggesting `'_`)
 - rust-lang#73515 (Add second message for LiveDrop errors)
 - rust-lang#73567 (Clarify --extern documentation.)
 - rust-lang#73572 (Fix typos in doc comments)
 - rust-lang#73590 (bootstrap: no `config.toml` exists regression)

Failed merges:

r? @ghost
@bors bors merged commit ae38698 into rust-lang:master Jun 23, 2020
@ehuss ehuss mentioned this pull request Jun 23, 2020
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This was referenced Jun 24, 2020
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yvt added a commit to r3-os/r3 that referenced this pull request Jun 25, 2020
@yvt
chore: update the target compiler version to nightly-2020-06-24
b096f68 
This commit includes work-arounds for the following changes in the
compiler:

- Raw pointers as const generic parameters are now forbidden.
  <rust-lang/rust#73398>

  This means the work-around for ICE caused by `&'static [_]` const
  generic parameters doesn't work anymore. An alternative work-around is
  yet to be implemented.

- Mutable references are now forbidden in all constant contexts except
  for `const fn`s.
  <rust-lang/rust#72934>

  Working around this change was as easy as mechanically replacing
  `const` with `const fn` for most cases. The only tricky case was the
  definition of `id_map` inside `build!`, which is a macro meant to be
  called inside a `const` item. The type of `id_map` isn't explicitly
  specified but is rather implied by a given configuration function, so
  this couldn't be mechanically replaced with a `const` item. To resolve
  this problem, I added an explicit type to `build!`'s signature.
Dylan-DPC-zz pushed a commit to Dylan-DPC-zz/rust that referenced this pull request Jun 25, 2020
@Dylan-DPC
Rollup merge of rust-lang#73673 - ehuss:fix-ptr-docs, r=oli-obk
da1e916 
Fix ptr doc warnings.

rust-lang#73398 added some stray backtick lines which cause warnings when the docs are built.
Manishearth added a commit to Manishearth/rust that referenced this pull request Jun 26, 2020
@Manishearth
Rollup merge of rust-lang#73673 - ehuss:fix-ptr-docs, r=oli-obk
57167a9 
Fix ptr doc warnings.

rust-lang#73398 added some stray backtick lines which cause warnings when the docs are built.
Manishearth added a commit to Manishearth/rust that referenced this pull request Jun 26, 2020
@Manishearth
Rollup merge of rust-lang#73673 - ehuss:fix-ptr-docs, r=oli-obk
d51c959 
Fix ptr doc warnings.

rust-lang#73398 added some stray backtick lines which cause warnings when the docs are built.
Manishearth added a commit to Manishearth/rust that referenced this pull request Jun 26, 2020
@Manishearth
Rollup merge of rust-lang#73673 - ehuss:fix-ptr-docs, r=oli-obk
91f8766 
Fix ptr doc warnings.

rust-lang#73398 added some stray backtick lines which cause warnings when the docs are built.
bjorn3
bjorn3 reviewed Jun 27, 2020
View reviewed changes
src/libcore/slice/mod.rs
if self.as_ptr() == other.as_ptr() {
return true;
}

// While performance would suffer if `guaranteed_eq` just returned `false`
// for all arguments, correctness and return value of this function are not affected.
#[cfg(not(bootstrap))]
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Why was this changed? This function is not const.

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Not yet, we're working towards that. I have a local branch where I'm trying to run this in -Zunleash-the-miri-inside-of-you mode.

RalfJung
RalfJung reviewed Jun 27, 2020
View reviewed changes
src/librustc_mir/interpret/intrinsics.rs
@@ -291,6 +291,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
let offset_ptr = ptr.ptr_wrapping_signed_offset(offset_bytes, self);
self.write_scalar(offset_ptr, dest)?;
}
sym::ptr_guaranteed_eq | sym::ptr_guaranteed_ne => {
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I just realized that this implementation will also be used by Miri, which is a bug. Can we somehow make it be used only during CTCE?

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doesn't miri fall back to this only if it has no own impl? So we can just give miri an impl that behaves differently.

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Miri prefers the CTFE impls, to make sure we test those properly.

I am working on a PR that adds these to Miri in a way that it prefers its own impls.

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Here it is: rust-lang/miri#1459

@oli-obk oli-obk deleted the const_raw_ptr_cmp branch June 27, 2020 09:41
@JohnTitor JohnTitor mentioned this pull request Jun 27, 2020
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Manishearth added a commit to Manishearth/rust that referenced this pull request Jun 28, 2020
@Manishearth
Rollup merge of rust-lang#73795 - JohnTitor:tests-for-const-fn-ptrs, …
2c1b732 
…r=oli-obk

Add some `const_compare_raw_pointers`-related regression tests

Closes rust-lang#71381
Closes rust-lang#71382
Closes rust-lang#71611
Closes rust-lang#72352

r? @oli-obk, the author of rust-lang#73398
@kanru kanru mentioned this pull request Jul 20, 2020
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@cuviper cuviper added this to the 1.46 milestone May 2, 2024
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@RalfJung RalfJung RalfJung approved these changes

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@bjorn3 bjorn3 bjorn3 left review comments

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